In-line probe recommendations

[dnjan]

I am looking for recommendations for some in-line probes.

Specifically, I would like to be able to continuously monitor:

Index of refraction (specific gravity)
Conductivity
pH

I would like to have fairly good precision, but would also like to get the probes and monitors for under about $3,000 total.

Possible?

Suggestions?

thanks!

 

[Boomer]

Don what is the reason behind why you do not want some kind of aquarium controller like Digital Aquatics or Apex ? Or is it these do not come with in-line probes ? But I'm sure they could work that out for you at nowhere near $3,000. You can get a Lab Grade like Honeywell / rack mount or others much cheaper than $3000.00, i.e., +$2,000. A top of the line lab grade is more like $3000. You are best off by far going to Cole-Parmer and telling a rep what you want. They are GREAT there, dealt with them for 20 years and there is multiple selections from them.

Second, Index of Refraction is not sg. There is no such thing as a sg or RI probe. There are digital RI refractometers though but not in-line. The International Std for Salinity is Conductivity, known as the K-15 Method. All you need is a pH probe and Conductivity/ Salinity probe with a controller/monitor. pH-Cond probes can range from $150 - $900 each. And controllers from $ 450 - $1,000. You can get want you for $1,000. And really have something for $2,000.

 

[dnjan]

Actually, it is a non-aquarium-related project, but the aquarium hobby/industry is the one connection I have to this kind of thing.

As far as the index of refraction measurements - I am looking at characterizing a mixture of disolved and suspended solids. IR gives a general indication of the total amount of material (whether disolved or suspended), but is somewhat sensitive to the material itself. Conductivity is great for disolved inorganics, but doesn't do much for the suspended solids. So I would like both measurements to better characterize these materials.
Most of the less-expensive IR meters I've used are catered to a specicif application. The one I am currently using gives a readout in brix, which I convert back to IR for my purposes. I mentioned SG because I thought that might be another application (saltwater SG) that a manufacturer might be providing a meter for.

I will look at the cole-palmer stuff. Thanks for the advise.

 

[Boomer]

Well, it is nice you clarified it more but it is still a shot in the dark unless I know what it is you are trying to measure. A RI meter is not the instrument to use as they are all designed for a specific. There are hand type Digital meters they you can cal for almost anything in one meter, such as those by Misco. Any shift in the POM, DOM, DIM and PIM will cause a shift in the RI and you will not know which one is doing it. I did find a in-line RI, to my surprise, for like $2,000. So, you need something for SS and DIM, which means a Conductivity/pH meter and a Turbidity Meter. A TM is a measurement of SS, Suspended Solids, be they POM or PIM and are not affected by DOM or DIM. And TM start at like $2000 and go to $5000 for in-line. There price is a funtion of their range. There is only one meter that meets you needs, which does it all and it is not in-line, a Horiba U-10 Water Quality Meter > pH, Temp, Conductivity, Salinity, O2 and Turbidity for ~$3000.00. And that U-10, a Hand-Held, is my dream meter

So, getting what you want in-line is possible for maybe $3000 but RI is NOT the way to go.